Method of Correcting Coordinates, and Defect Review Apparatus

ABSTRACT

The present invention provides a method of correcting coordinates so as to quickly and properly arrange a sample in a field of view in a review apparatus for moving a sample stage onto the specified coordinates to review the sample. A review apparatus according to the present invention, which is a review apparatus for moving a sample stage onto coordinates previously calculated by a checking apparatus to review the sample, has a function of retaining a plurality of coordinate correction tables to correct a deviation between a coordinate value previously calculated by a checking apparatus and an actual sample position detected by the review apparatus. The review apparatus evaluates correction accuracy of the plurality of coordinate correction tables and applies one of the coordinate correction tables with the maximum evaluation value.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuing application of U.S. application Ser.No. 11/753,966, filed May 25, 2007, which claims priority under 35U.S.C. §119 to Japanese Patent Application No. 2006-146042, filed May26, 2006, the entire disclosure of which are herein expresslyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and apparatus for correctingcoordinates so as to arrange a sample in a field of view in a reviewapparatus for moving a sample stage onto the specified coordinates toreview the sample. More particularly, the present invention relates toan apparatus for deciding a position for review based on information ofa position of a defect detected by a higher-level checking apparatuslike an SEM (Scanning Electron Microscope) based defect reviewapparatus.

2. Background Art

In semiconductor manufacturing, it is important to find defectsappearing during a manufacturing process in early phases and takemeasures against the defects in order to ensure yield enhancement. Inrecent years, even slight defects have nonnegligible effects on yieldsas semiconductors become smaller, hence making the size of defects to bereviewed smaller.

An SEM-based defect review apparatus is an apparatus for reviewing suchslight defects. The apparatus generally reviews defects based onpositions of the defects detected by an optical checking apparatus. Inthis way, before the SEM-based defect review apparatus reviews in detailthe defects detected by the checking apparatus, the checking apparatusexecutes the defect detecting processing as preprocessing. So thedetecting apparatus is herein defined as a “higher-level” apparatus.

A defect is reviewed manually using the SEM-based defect reviewapparatus as follows: a sample stage is moved onto coordinates outputtedby the higher-level checking apparatus for image pickup at a lowmagnification (in a wide field of view); after a position of the defectis confirmed visually, the sample stage is moved such that the defectposition is in the middle of the field of view; and a defective image ispicked up at a high magnification (in a small field of view). Thesesteps have been automated as the ADR (Automatic Defect Review). In theADR, a defect appearing in a field of view of an image at a lowmagnification is detected using image processing, and then a samplestage is moved such that the detected defect is in the middle of thefield of view to pick up a high magnification image at a relevantmagnification for review of details of the defect. From the perspectiveof the image processing, a low magnification image is preferablymagnified to fully magnify the defect for the review. However, a toohigh magnification may cause the defect to be out of the view field if adeviation of the position is substantial. Because of this, ADRconfiguration has a difficulty in setting a parameter of a magnificationfor a low magnification image, so that user experience is needed for thesetting. This is not preferable since the ADR steps depend on user'sskill based on the user experience.

To address the above problem, JP Patent Publication (Kokai) No.2001-338601 (2001) proposes a method of efficiently performing a task ofsetting a magnification for a low magnification image including: afunction of visualizing a deviation between a defect position outputtedby a higher-level checking apparatus and a defect position detected inthe ADR by displaying the deviation as a vector on a wafer map; afunction of correcting a coordinate system such that the deviation isminimum; and a function of optimizing the magnification for the lowmagnification image depending on the amount of the detected deviation.These functions can visualize a deviation, optimize a correction table,and optimize a magnification for a low magnification image.

However, if there are a plurality of higher-level checking apparatuses,or if different deviation tendencies are shown depending on, forexample, check conditions or a deviation tendency changes over time evenin the case of that there is only a single checking apparatus, theoptimal correction result cannot be obtained using a single correctiontable.

SUMMARY OF THE INVENTION

In view of the foregoing, an object of the present invention is toprovide a method and an apparatus for correcting coordinates so as toarrange a sample in a field of view properly and quickly in a reviewapparatus for moving a sample stage onto the specified coordinates toreview the sample.

To solve the above problems, the present invention is mainlycharacterized in that a plurality of coordinate correction tables areretained, correction effectiveness of the coordinate correction tablesin review is evaluated, and the review is performed using an optimalcorrection table.

More specifically, the present invention relates to a review apparatusfor moving a sample stage onto coordinates (a defect position on awafer), for example, previously calculated by a checking apparatus so asto review the sample. The review apparatus according to the presentinvention identifies a combination of the checking apparatus calculatinga coordinate value and a condition (for example, a check mode) tocalculate the coordinates. Based on the identified combination of saidapparatus and said calculation condition, one of a plurality ofcoordinate correction tables is selected that are provided incorrespondence to the combination of said checking apparatus and thecalculation condition of said coordinates. Then, the coordinatescalculated by said checking apparatus are corrected according to saidselected coordinate correction tables. In this way, an optimalcorrection result can be obtained quickly and properly compared to theconventional case that correction table switching depends on a checkingapparatus ID.

Furthermore, the present invention relates to a review apparatus formoving a sample stage onto coordinates (a defect position on a wafer),for example, previously calculated by a checking apparatus so as toreview the sample, including: a plurality of coordinate correctiontables to correct a deviation between a pre-calculated coordinate valueand a sample position on said review apparatus; and coordinatecorrection table evaluation means for evaluating accuracy of thecorrection according to said plurality of coordinate correction tables.Based on the result of the evaluation by said table evaluation means,one of said plurality of coordinate tables is chosen for use to correctsaid pre-calculated coordinate value. In this way, even when thecoordinate correction table selected based on the combination of thechecking apparatus ID and the check mode is no longer optimal due tochange over time, a more suitable table can be used to correct the aboveamount of deviation.

Other features of the present invention will become apparent in thefollowing best embodiment and the attached drawings to practice thepresent invention.

According to the present invention, an optimal coordinate correctiontable can be automatically selected for use from a plurality ofcoordinate correction tables. This can reduce phenomena in that areviewed object is out of a field of view because a coordinatecorrection table is not a proper one. Further, using an optimalcorrection table, the amount of a deviation can be reduced and a reviewmagnification to identify a defect position can be increased. This makespossible to improve defect detection performance by increasing a lowmagnification (a magnification to detect a defect position) particularlyin the ADR.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of basic configuration of an SEM-basedsemiconductor defect review apparatus;

FIG. 2 is a diagram of network connection between checking apparatusesand a review apparatus;

FIGS. 3A and 3B are diagrams illustrating different tendencies ofdeviations depending on check modes: FIG. 3A shows an instance of vectordisplay for the deviation tendencies, and FIG. 3B is a diagram of thenetwork connection between checking apparatuses and a review apparatus;

FIG. 4 is a flow diagram of a function of automatically switching to acoordinate correction table;

FIG. 5 shows an example of switching to a coordinate correction tablewith considering weight coefficients;

FIG. 6 is a graph of a result according to the correcting coordinatecorrection tables;

FIG. 7 is a flow diagram of a function of automatically updating thecorrection tables; and

FIG. 8 shows a display screen of a result of evaluation of a correctiontable.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the attached drawings, embodiments of the present inventionwill be described below. A review apparatus according to a firstembodiment prepares a plurality of coordinate correction tables toswitch to one of the coordinate correction tables statically dependingon a checking apparatus and its check mode. On the other hand, a reviewapparatus according to a second embodiment prepares a plurality ofcoordinate correction tables to always switch dynamically to one of thecoordinate correction tables evaluated as an optimal one by performingthe evaluation in parallel to the review, thereby obtaining a bettercorrection result.

First Embodiment

FIG. 1 is a cross-sectional view of configuration of an SEM-basedsemiconductor defect review apparatus (a review apparatus) according toan embodiment of the present invention. The SEM-based defect reviewapparatus in FIG. 1 consists of an electron gun 101, a lens 102, adeflector 103, an objective lens 104, a sample 105, a stage 106, asecondary particle detector 109, an electro-optic system control unit110, an A/D converting unit 111, a stage control unit 112, a centralcontrol unit 113, an image processing unit 114, a display 115, akeyboard 116, a storage device 117, a mouse 118 and the like.

An electron beam 107 emitted by the electron gun 101 converges on thelens 102, is deflected on the deflector 103, converges on the objectivelens 104 and then is radiated onto the sample 105. Secondary particles108 such as secondary electrons or reflected electrons are generatedfrom the sample 105 radiated with the electron beam 107 depending on aform or materials of the sample. The generated secondary particles 108are detected by the secondary particle detector 109 and converted intodigital signals by the A/D converting unit 111 to form an SEM image. Theproduced SEM image is subjected to image processing such as defectdetection executed by the image processing unit 114. The lens 102, thedeflector 103 and the objective lens 104 are controlled by theelectro-optic system control unit 110. A sample is positioned on thestage 106 controlled by the stage control unit 112. The central controlunit 113 interprets an input from the keyboard 116, the mouse 118 or thestorage device 117 to control the electro-optic system control unit 110,the stage control unit 112, the image processing unit 114 and the like,and outputs details of the processing on the display 115 and to thestorage device 117 as necessary. The storage device 117 storescoordinate correction tables and a control program illustrated inflowcharts in FIGS. 4 and 6 as described below.

FIG. 2 is a diagram of network connection between higher-level checkingapparatuses and a review apparatus according to the embodiment of thepresent invention. A network (201) connects to a checking apparatus (ID:1) (202), a checking apparatus (ID: 2) (203), a checking apparatus (ID:3) (204) and a review apparatus (205). The network 201 can also connectsto a plurality of review apparatuses. A review apparatus connects to astorage device (206). The storage device can be integrated into thereview apparatus or separated from the review apparatus for the networkconnection. The storage device saves coordinate correction tables (207,208 and 209) corresponding to the checking apparatuses. The storagedevice switches to an optimal coordinate correction table based on an IDof a checking apparatus when the review is executed. In FIG. 2, thecoordinate correction tables correspond to the checking apparatusesone-to-one. For example, a coordinate correction table A is selectedwhen the checking apparatus (ID: 1) is used to detect a defect, acoordinate correction table B is selected when the checking apparatus(ID: 2) is used to detect a defect, and a coordinate correction table Cis selected when the checking apparatus (ID: 3) is used to detect adefect. Since the checking apparatuses correspond to the coordinatecorrection tables one-to-one as described in the above, one of thechecking apparatuses sends information of a defect position and achecking apparatus ID to at least a review apparatus, and the reviewapparatus selects a coordinate correction table corresponding to thechecking apparatus ID.

FIG. 3 is a drawing illustrating processing in the case of differenttendencies of deviations of detected coordinates depending on checkmodes of higher-level checking apparatuses. Hereinafter, a check modemeans a manner to detect a defect including, for example, a mode todetect a defect by exposing light onto a wafer at an angle, a mode todetect a defect by looking a wafer from the above and the like (such asa mode to detect a defect by scanning a wafer on XY coordinates or amode to detect a defect by scanning a wafer on rotating coordinates).FIG. 3A is one example of display of differences between coordinatevalues detected by the higher-level checking apparatus and coordinatevalues detected by the review apparatus using vectors (also disclosed inJP Patent Publication (Kokai) No. 2001-338601 (2001)). FIG. 3A showsthat, for example, when a position is farther apart from the center ofthe wafer, the deviation tends to be larger toward the wafer peripheryin a check mode 1 (301), while a deviation toward the left tends to belarger in the left side of the wafer in a check mode 2 (302). In suchinstances, when the coordinate correction table switching depends ononly an ID of a checking apparatus, it is difficult to obtain goodcorrection results in both of the check modes because of differenttendencies of deviations on coordinates depending on check modes.

In view of the above difficulty, this embodiment has a function ofswitching to a coordinate correction table depending on a check mode ofthe checking apparatus in addition to the function of switching to acoordinate correction table based on a checking apparatus ID. Althoughan instance of different deviation tendencies depending on check modesis assumed herein, the different deviation tendencies depending on checkmodes may be due to a defect position identify algorithm of a checkingapparatus or operation of a sample stage of the checking apparatus.Furthermore, the accuracy may decrease in detecting a defect position bya checking apparatus over time, so that the apparatus generally needs tobe maintained regularly.

FIG. 3B illustrates a function of switching to a correction tabledepending on a check mode (a condition for a checking apparatus todetect a defect and calculate coordinates of the defect). A checkingapparatus (304) and a review apparatus (308) connect to a network 303.The review apparatus connects to a storage device (309). The storagedevice can be integrated into the review apparatus or separated from thereview apparatus for the network connection. The checking apparatus 304sends coordinates of a detected defect and information of a check modetogether to the review apparatus. The information of a check modeincludes, for example: information of a mode to detect a defect byexposing light onto a wafer at an angle, a mode to detect a defect bylooking a wafer from the above and the like (such as a mode to detect adefect by scanning a wafer on XY coordinates or a mode to detect adefect by scanning a wafer on rotating coordinates) as described in theabove; information of sensitivity of the checking apparatus in thedetection; information of a serial number of the detecting apparatus andthe like.

The review apparatus 308 receives the information of a check mode fromthe checking apparatus 304 and determines a check mode of the checkingapparatus from the information. Then, the review apparatus 308 switchesto one of the coordinate correction tables (310, 311 and 312) based onthe determined check mode. The coordinate correction tables areconfigured to perform coordinates correction optimally for any of thecheck modes. For example, the tables are used to obtain a deviationbetween coordinates actually detected in a check mode of the checkingapparatus and coordinates detected by the review apparatus by astatistically process.

As described in the above, the correction table switching depends on apre-determined check mode of a pre-determined checking apparatus,enabling to obtain a good correction result in an instance withdifferent deviation tendencies depending on the check modes.

Second Embodiment

As described above, the review apparatus according to the firstembodiment selects a coordinate correction table statically incorrespondence to a check mode of the checking apparatus. That is, achecking apparatus and a check mode uniquely decide a coordinatecorrection table.

However, because of temporal changes or the like in the apparatus, acoordinate correction table decided uniquely depending on a check modeis not always an optimal table. Although periodical maintenance iseffective to the temporal changes as described above, its steps must beextremely complicated.

To address the above problem, according to a second embodiment, even ifa checking apparatus and/or a review apparatus change with a certaintendency over time, a plurality of coordinate correction tables areprepared in correspondence to the temporal changes, or a plurality ofcoordinate correction tables are prepared in correspondence only to aplurality of check modes to always switch dynamically to a coordinatecorrection table evaluated as an optimal one by performing theevaluation in parallel to the review, thereby obtaining a bettercorrection result.

The system configuration (FIG. 2) and the configuration of the reviewapparatus (FIG. 3) are similar to those of the first embodiment, andtherefore will not be further described herein.

FIG. 4 is a flowchart illustrating a function of automatically switchingto a coordinate correction table. This function is operated by thecentral control unit 113 unless otherwise noted. The coordinatecorrection table switching is automatic herein although a user can setfor the coordinate correction table switching. That is, this embodimentis characterized in that a deviation tendency is evaluated based on acoordinate value outputted by a checking apparatus and a coordinatevalue of a sample position detected in the review to switch to anoptimal coordinate correction table in the review.

In FIG. 4, at the start of the review (401), a coordinate correctiontable in its initial setting is in use (402). The coordinate correctiontable in its initial setting can be configured as any table, orconfigured based on a previous processing result as described below (seeFIG. 6).

During the review (403 to 409), if the coordinate correction tableselecting function is enabled (the function is ON) (404), evaluationvalues of the coordinate correction tables are calculated (405), amaximum evaluation value is further calculated (406), and a coordinatecorrection table with the maximum evaluation value is selected (407).These processes allow for review using an optimal coordinate correctiontable even if a tendency differs from a default coordinate correctiontable.

An equation (1) is an exemplary formula of calculating an evaluationvalue E of a coordinate correction table. The evaluation value isdefined so as to be higher for a smaller deviation amount D after thecorrection by a coordinate correction table. Generally, a review orderis often decided such that the amount of stage movement is minimum toimprove throughput. In that case, samples will be reviewed from theclosest sample in order.

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack & \; \\{E_{n} = \frac{1}{\sum\limits_{i = 1}^{n}{W_{i}D_{i}}}} & (1)\end{matrix}$

Since deviation tendencies are local in most cases, close samples oftenhave similar deviation tendencies. A value is effective that isevaluated by weighting the tendency of the closest deviation in the caseof a review order with the minimum distance of a movement. In that case,an increasing function of a weighting coefficient W for the review orderis effective. For example, it is effectual to ignore the deviationamount previous to closer points. Alternatively, in the case of asufficient calculation cost including a processing time, the weightingfunction can be effectually a function of a distance between a reviewpoint to calculate an evaluation value and a review point with thepreviously calculated deviation amount.

FIG. 5 shows one example of switching to a coordinate correction tablewith considering the weight coefficient described in the above. In FIG.5A, there are seven review points on a wafer. A point on the waferindicates checked coordinates (x₀, y₀) outputted by a checkingapparatus, and also indicates detected coordinates (x, y) detected bythe review apparatus as shown by the head of the arrow. Two coordinatecorrection tables are evaluated herein and coordinates correctedaccording to the tables are correction coordinates 1 (x₁, y₁) andcorrection coordinates 2 (x₂, y₂). For simplicity, a correcting equationfor the correction tables are simplified to calculate the correctioncoordinates 1 by the equation (2) and the correction coordinates 2 bythe equation (3):

[Formula 2]

(x ₁ ,y ₁)=(x ₀−1,y ₀+2)  (2)

[Formula 3]

(x ₂ ,y ₂)=(x ₀+1,y ₀−2)  (3)

Set the weight coefficient W to be ½ for two previous points and ignoredeviation tendencies of points previous to the two points to get theequation (4):

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 4} \right\rbrack & \; \\{W_{i} = \left\{ \begin{matrix}{1\left( {i = 1} \right)} \\{{1/2}\left( {{{i \geq {2\mspace{14mu} {and}\mspace{14mu} i}} = n},{n - 1}} \right)} \\{0\left( {i \geq {3\mspace{14mu} {and}\mspace{14mu} i} \leq {n - 2}} \right)}\end{matrix} \right.} & (4)\end{matrix}$

The evaluation value E of a correction table is calculated using thefollowing equation (5) based on the equations (1) and (4):

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 5} \right\rbrack & \; \\{E_{i} = \left\{ \begin{matrix}{\frac{1}{D_{i}}\left( {i = 1} \right)} \\{\frac{2}{D_{i} + D_{i - 1}}\left( {i \geq 2} \right)}\end{matrix} \right.} & (5)\end{matrix}$

where D₀=0.

FIG. 5B shows coordinates checked by the checking apparatus and thereview apparatus, corrected coordinates calculated using the equations(2) and (3), and specific numerical value examples of evaluation valuescalculated using the equation (5). Setting a table 1 (equation (2)) asan initial correction table, the review is executed using the correctiontable 1 from the first point through the fifth point inclusive, and acorrection table 2 will be used after the fifth point where anevaluation value of the table 2 exceeds that of the table 1.

Referring to FIG. 6, the switching to a table will be described moreconceptually. FIG. 6 is an exemplary graph representing a correctionresult using coordinate correction tables A (604), B (605) and C (606)with a review order (601) on the abscissa axis and deviation amounts(602) on the ordinate axis. Inverse numbers of evaluation values (603)instead of the deviation amounts (602) on the ordinate axis can alsoyield the same graph tendency. If the coordinate correction table A(604) is selected as an initial table, the coordinate correction table C(606) is used after the second point according to an evaluation resultat the first point. Further, the coordinate correction table B (605) isselected after a crossing point (607) according to an evaluation resultat the crossing point (607). Similarly, If the coordinate correctiontable C (606) is selected as the initial table, the coordinatecorrection table C (606) continues to be used till the crossing point(607); the coordinate correction table B (605) is used after thecrossing point (607) according to an evaluation result at the crossingpoint (607). Further, if the coordinate correction table C (606) isselected as the initial table, the coordinate correction table C (606)continues to be used after the second point according to an evaluationresult at the first point, and the coordinate correction table B (605)is used after the next point to the crossing point (607) according to anevaluation result at the crossing point (607). In this way, an optimalcorrection table is used during the review to allow search for a defectwith the minimum deviation amount. In addition, the computationalcomplexity of the comparison and evaluation processing on the coordinatecorrection tables is so small that the processing can be executedwithout reducing ADR throughput.

FIG. 7 is a flowchart illustrating a function of automatically updatingthe correction tables. This function is operated by the central controlunit 113 unless otherwise noted.

In FIG. 7, at the end of the ADR (701), if an automatic update functionfor the coordinate correction tables is enabled (702), evaluation valuesof the coordinate correction tables to be compared are calculated (703).Next, a coordinate correction table with the maximum evaluation valueamong the coordinate correction tables are calculated (704), and thenthe table is set as an initial coordinate correction table for ADR(705). The coordinate correction tables for the comparison can be newlycreated coordinate correction tables to be added based on a tendency ofdeviation measured in previous ADR, or coordinate correction tables tobe added that are updated by adding measurement data to the existingcoordinate correction tables. The coordinate correction and the creationof the coordinate correction tables can be performed as described in JPPatent Publication (Kokai) No. 2001-338601 (2001), or otherwise. Theequation 6 is an exemplary calculating formula of an evaluation value toautomatically update the coordinate correction tables. As opposed to theequation 1, the weight coefficient W reflecting a sample position isfixed (W=1).

$\begin{matrix}\left\lbrack {{Formula}\mspace{14mu} 6} \right\rbrack & \; \\{E_{n} = \frac{1}{\sum\limits_{i = 1}^{n}D_{i}}} & (6)\end{matrix}$

FIG. 8 is an exemplary display screen for an evaluation result ofcoordinate correction tables. A name or ID of a checking apparatus to beevaluated is displayed in a box 801 and a check condition is displayedin a box 802. Coordinate correction tables to be evaluated can beselected in boxes 803, while deviation tendencies are displayed asvectors in circles 804 on a wafer map. Average values of deviationamounts are displayed in boxes 805, while values 3σ (triple of variance)(statistically, most information is included within a range of 3σ) aredisplayed in boxes 806. Values FOV (Field of View) representing sizes ofrecommended fields of view obtained from the values 3σ are displayed inboxes 807. Further, recommended magnifications corresponding to therecommended FOV are displayed in boxes 808.

To notify a checking apparatus of the information as described above,one of send buttons 809 is pushed. A sending function is preferablyautomatic sending, but a user can push the send button 809 to notify thechecking apparatus when the user desires to notify. In the automaticsending, the sending is performed only if a condition is satisfied, forexample, a deviation is over a certain value or difference from aprevious deviation is more than a certain value. Such automatic sendingcan be used to determine whether or not the checking apparatus needsmaintenance. Although direct notification to a checking apparatuscalculating coordinates is described herein as an example, notificationto a system managing the checking apparatus has similar effect.

As described hereinabove, in the review apparatus according to thesecond embodiment, the coordinate correction table switching is dynamicin correspondence to the change, thereby obtaining a good correctionresult even if a desired correction result cannot be obtained using acoordinate correction table initially selected depending on, forexample, temporal changes in a checking apparatus or a review apparatus.

Further, a coordinate correction table is automatically updated in thesecond embodiment, thereby allowing to use an optimal correction tableand obtain a good correction result after the start of the coordinatescorrection processing.

Furthermore, in the second embodiment, the amount of a deviation of adefect detected positions between a checking apparatus and a reviewapparatus is notified to the checking apparatus. If the deviation amountis too large, an administrator can maintain the checking apparatus.

Meanwhile, the present invention can also be embodied in a softwareprogram code for realizing the functions of the embodiments. In thatcase, a system or an apparatus is provided with storage media recordingthe program code, and the program code is read out that stores acomputer (or CPU, MPU) for the system or the apparatus in the storagemedia. The program code read out from the storage media realizes thefunctions of the previously mentioned embodiments, and the presentinvention is embodied in the program code and the storage media storingthe code. The storage media for supplying the program code includes, forexample, a floppy (R) disc, a CD-ROM, a DVD-ROM, a hard disk, an opticaldisc, an optical magnetic disc, a CD-R, a magnetic tape, a non-volatilememory card, a ROM and the like.

An OS (operating system), for example, running on the computer canperform part or whole of actual processing based on indications by theprogram code, such that the previously mentioned functions of theembodiments can be realized by the processing. The CPU in the computercan also perform part or whole of actual processing based on indicationby the program code after the program code read out from the storagemedia is written into a memory on the computer, such that the previouslymentioned functions of the embodiments can be realized by theprocessing.

The functions can be also achieved such that the software program codefor realizing the functions of the embodiments is distributed via anetwork, stored in storage means such as the hard disk or the memory inthe system or the apparatus or storage media such as a CD-RW or a CD-R,and executed after the program code is read out that is stored in therelevant storage means or the relevant storage media by the computer (orCPU, MPU) for the system or the apparatus.

1. A review apparatus for moving a sample stage onto pre-calculatedcoordinates to review a sample, comprising: identification means foridentifying a combination of an apparatus for calculating a coordinatevalue and a calculation condition of the coordinates; a plurality ofcoordinate correction tables provided in correspondence to thecombination of the apparatus for calculating said coordinate value andthe calculation condition of said coordinates; table selection means forselecting one of said coordinate correction tables based on thecombination of said apparatus and said calculation condition identifiedby said identification means; and coordinate correction means forcorrecting the coordinates calculated by the apparatus for calculatingsaid coordinate value using said coordinate correction table selected bysaid table selection means.